This book highlights a multiplicity of pathways, i.e. ways of thinking and implementing participatory approaches in a perspective of sustainability of socio-ecosystems. The book focuses on three main elements that constitute the core of the CoOPLAGE pathways: (self-)engineering and evaluation of participatory processes, modelling and simulation, and planning. These pathways are ongoing: there are as many instances of each tool presented in this book as there are territories where the tool has been implemented. Our research is made and shaped by the socio-ecological system on and for which it works. It is truly stakeholder driven. In the conclusion, we present other tools that have been developed before the publication of this book but could not be included. We also address pending issues and way forward such as social extension, reassessing long term impacts, extending digital participation, dealing with emotions and affects, or linking with prospective thinking and anticipation.